A true target signal extraction method for defending against dense false target jamming in multistatic radar systems

Dense false target jamming (DFTJ) is a typical form of active jamming that generates numerous false targets along the radar line of sight, significantly degrading the detection and tracking performance of radar systems. In multistatic radar systems with spatially separated receivers, jamming signals originating from the same source become highly correlated across various receivers after compensating for their delay and Doppler frequency differences, whereas true target echoes remain weakly correlated because of varying observation geometries. On the basis of these differences, we propose a method for extracting true target signals from jammed echoes. First, the jamming signals are aligned across different receivers by compensating for their amplitude, delay, and Doppler frequency differences. The compensated and pulse-compressed echoes are then stacked into a signal matrix, where the false targets remain nearly invariant across different columns and thus form a low-rank component, while the true targets exhibit amplitude, delay, and Doppler frequency variations, manifesting as sparse high-rank components. Based on this structural distinction, we formulate a robust principal component analysis problem for extracting the true target signals and solve it using the block coordinate descent approach. To satisfy real-time processing demands, we further develop a sequential processing-based version of the proposed method. The numerical simulation results demonstrate the effectiveness of the proposed method, which shows stable performance under different DFTJ strategies, jamming parameters and target characteristics.